Among the raft of recent and upcoming Microsoft upgrades, Windows 8 towers in importance but its chances for success remain cloudy among enterprise customers.

While Windows 8 is getting automatically pushed onto new PCs and tablets to consumers, its acceptance in the enterprise is expected to be a tougher sell. Most enterprises have either recently upgraded from XP to Windows 7 or are in the process of doing so, and thus unlikely to embark again so soon on another OS refresh, according to various surveys.

It was on the strength of its dominant OS position on desktops and laptops that Microsoft built its successful product portfolio for enterprises, including client-side applications like Outlook, Word, Excel and PowerPoint and server-side software like SQL Server, SharePoint and Exchange.

As the company worked furiously throughout most of 2012 to put the finishing touches on Windows 8, the sense of urgency among its executives was evident, given the anemic share of Windows 7 on tablets, devices which have become tremendously popular not only among consumers but also in workplaces. With Windows 8, which sports a radically different interface optimized for touchscreens, CEO Steve Ballmer and his generals expect Microsoft to significantly improve its share of tablet OSes. In the past two years or so, droves of people have brought to work their personal iOS and Android smartphones and tablets and Windows has a minuscule share of those markets. As with Windows 8 in tablets, Microsoft has high hopes for Windows Phone 8 to improve its smartphone OS sales.

But so far, Windows 8 has gotten mixed reviews, and industry analysts, Microsoft partners and customers remain divided on their expectations for success of the new OS.

Mark Newton, vice president of operations at TeleMate.Net Software, a Microsoft Certified Partner that makes an Internet filter appliance for businesses called NetSpective, calls the new Windows 8 touch-optimized interface "annoying" and "unintuitive." He refers to the new interface's Live Tiles icons as "big square blotches on the screen" that "don't make efficient use of the desktop space."

The interface, he said, is clearly for tablets. "It doesn't play well in the desktop."

And while Windows 8 also has an alternate interface that more closely resembles the traditional Windows 7 desktop, Newton is also unimpressed by it. He dislikes that it doesn't have the Start button, and that it doesn't offer Windows 7's familiar menu system.

He would have been less irritated if Microsoft had made it possible for IT administrators to set the traditional desktop as the main, default interface in their company's PCs, but that isn't an option.

At TeleMate.Net, he put Windows 8 on a couple of tech-savvy employees' PCs and they quickly requested to be switched back to Windows 7. "They said to put Windows 7 back in there because they had to use their computers."

TeleMate.Net has Windows 8 on the machines of a few developers who are working to tweak the NetSpective software for the new OS, but the company will keep the other 20 or so other employees on Windows 7.

"I'm not going to push Windows 8 out to everyone's desktop until there's a valid and compelling reason to do so, and right now it doesn't exist. Windows 7 is very stable, very robust," he said.

He would have made the same decision at his previous job, where he held a similar position, but oversaw about 5,000 end users.

"There's no way I would have ever agreed to deploy Windows 8 to 5,000 desktops and then have to go and figure out how to explain to people how to use the new interface and train them," he said.

In other places, Windows 8 is getting a warmer reception, including by early adopters Seton Hall University, British Telecom and the Emirates airline.

"Windows 8 is great for business because it delivers the experiences people love while providing organizations with the IT controls they require," said Jason Campbell, a Microsoft senior product manager.

"Many organizations across a wide variety of industries are taking advantage of Windows 8," he added.

At CB Engineers in San Francisco, IT Director Jack Mou plans to replace all company laptops—about 15—with Windows 8 tablets and laptops next year, displacing also a number of iPads employees bring from home.

But although Mou considers Windows 8 superior to its predecessor, he concluded that on the desktop it doesn't offer enough improvements to warrant upgrading from Windows 7.

"For the desktop deployment, unless otherwise requiring touchscreen and [stylus] pen inputs, I don't find it necessary to upgrade if you are already on Windows 7," he said via e-mail.